Just in time for the holidays: in December 2013 alone, sales hit $1 billion.

We all sure spent a lot on apps in 2013. $10 billion worth, in fact, according to Apple.

On Tuesday, Cupertino also announced that App Store sales hit $1 billion in December 2013 alone, the most successful month in company history.

As Macworld points out, it initially took Apple two years to reach $3.6 billion in App Store sales—a figure the company averaged during every quarter of 2013. Last summer, Forrester Research noted that Apple “leads the App Store economy” and that “Apple mobile app developers earned around 2.6 times more revenue than Android developers in Q1 2013.”

More broadly, the app economy worldwide continues to zoom forward. In September 2013, Gartner estimated that total revenue across all app stores would reach $26 billion in 2013. Surprisingly, the majority of apps remain free across all stores, the analysis firm noted.

"Free apps currently account for about 60 percent and 80 percent of the total available apps in Apple's App Store and Google Play, respectively," said Gartner analyst Brian Blau in a statement at the time. "iOS and Android app stores combined are forecast to account for 90 percent of global downloads in 2017. These app stores are still increasingly active due to richer ecosystems and large and very active developer communities.”